Hydraulic shock absorber



G. M. MAGRUM EVAL HYDRAULIC sHocK tAIBSORBER Sept. 4, 1945.

Filed April 1.0,v 1942 Patented Sept. 4, 1945 tourna!)I HYDRAULIC SHOCK ABsoRBER Gervase M. Magrum and Bernard E.

assignors to Houdaille-Hershey Buffalo, N. Y.,

OConnor,

' Corporation, Detroit, Mich., a corporation of l v Michiganl 1 'application April 1o, 1942, ser1a1No.43s,4o4

(C1. zii- 45)` 4 Claims.

This invention relates to hydraulicshockv absorbers, particularly ofthe" direct acting piston type such as disclosed in Magrum Patent No. 2,273,878, 'February 24, 1942, the important object being to provide improved valving means for controlling the ow of theV displaced hydraulic fluid during operation of the shock absorber.

A shock absorber embodying the features of our invention is shown on the drawing, in which:

.Figure 1 is a longitudinal diametral section of the shock absorber;

Figure 2 is an enlarged valving assembly; and Y Fizgure 3 is a section on plane III-III of Figure Y r The shock absorbershown comprises the cylinder I internally threaded at one end to receive the plug II formingV the cylinder head, the plug having openings or passages I2 by means of which it may be secured to a structure to be controlled by the shock absorber. Packing I3 compressed in` a channel- I4 in the plug seals this end of the cylinder against leakage.

The cylinder has the bore I5 in Vwhich the piston P operates, the piston rod I6 extending from the piston through thesmaller bore I1 of the cylinder and has at-its outer end anv eye I8 or other suitable fitting -for `connection with structure to be controlled Vby the shock absorber. Packing I9 surrounds 'the piston rod and seals against fluid leakag'ewv v The piston P has the chamber 20 threaded at its inner end to receive the annular valve seat member 2| which terminates in the annular seating edge 22 for the valve disk 23 which has the annular stern 24 extending therefrom into a. sleeve cross section of the 25. This sleeve has the flange 26 engaging in the seat member 2l and slabbed oii to provide passageways 21. The sleeve is secured to the stem of the valve 23 as by means of a; pin 28. The sleeve has the outer end wall 29 with a port 30 therethrough, and within the sleeve is the cup valve 3I normally held by a spring 32 seated with its bottom against the outer end of the valve stem 24. Figure 1 shows the bottom of the cup valve provided with a restricted oriiice 33, and the sleeve has one or more ports 34 normally closed by the cup valve 3|.

A spring 35 in the cylinder bore I5 abuts the plug I I and the inner end of the piston and tends to hold the piston and its rod I6 in outer position and to resist inward movement thereof. The outward movement of the piston is limited by the engagement thereof with the shoulder 36.

The piston chamber 20 is connected by passages 31 in the piston head with the cylinder space 38 in front of the piston. The cylinder has the extension 39 providing an expansion chamber 49 communicating at its bottom through the passage M with the cylinder space 38. The chamber 4u is closed by a cover 42,v and a ller plug 43 is provided for the chamber.

Within the piston chamber 20 is thespring Il abutting the piston head and the valve disk 23 for resisting opening of the valve upon inward shift of the piston in the cylinder. is comparatively heavy so of the valve 23 for blow-ofi except under sudden or abnormal pressure conditions. In other words, full opening or blow-ofi of `the valve Lshould kbe delayed by the spring until there has beenY a maximum absorption by the shock absorber of the energy which it is tol control. With such valve operation, the shock absorber can be emciently utilized on machine or other guns for maximum absorption of the recoil before blow-oir operation ofthe valve. Where the foull-benet of the blow-off valve is desired, the vorifice 33 in the cup valve 3| may be omitted, as shown onoFigure 2 the only escape then of the fluid in the cylinder during inward travelrof upon the energy exerted by the piston against the fluid in the outer end of the cylinder, the valve 23 will open to a corresponding vvde'greelfor restricting the ow between the `valve and theseating edge 22. Under sudden or prolonged inward movement of the piston under comparatively heavy pressure the built up fluid pressure will unseat the valve for blow-off flow 'through the piston.

In some installations of the shock absorber, the restricted orice 33 may be desirable so that under ordinary inward movements of the piston the fluid can escape through the orifice, and the blow-off valve will operate only when the pressure of the displaced fluid becomes excessive or abnormal. When the shock absorber is relieved, the spring 35 will restore the piston to its outer position, and during such movement the cup valve will open against its comparatively light spring 32 for comparatively free flow of iiuid through the piston. The spring 35 assists the valving structure in resisting and absorbing the inward movement of the piston in the cylinder.

The iiuid displaced by the entrance of the piston rod into the cylinder will be received in the expansion chamber 40 to be returned to the cylinder when the piston is restored to its outer position.

We have shown a practical and efcient embodil Thisl springA as to resist full opening l the piston being through the ports 21 and past the valve 23. Dependingy sorber comprisingan` annular valve seat memberl having an annular seating edgeat its Yinner end,`

a sleeve extending through said seat member and having a ange thereon having sliding fit in said seat member, a valve disk for seating on Vsaidannular seating edge, an annular stem extending outwardly from said valve diskfintd'the inner. end" of said sleeve and secured 'toJSaidA sleeve for movement of said sleevewith said valve, a comparatively heavy spring tending to hold said valve against said seating edge, said flange beingslabbed oil at opposite sides to leave passageway between said sleeve and said seating member for flow of fluid inwardly against'said valve disk foropening thereof, a check valvefin the outer end of saidsleeve normally abutting the outer end ofV said stem for closing saidfstemagainstluid flow inwardly therethrough and for opening said rstem passageway for outwardv now therethrough.

2. A valving assembly for a hydraulic shockabsoi-'oerY comprising an annular valve seat member having an annular seating edge at its inner end, a sleeve extending through through said seat meinberand having a flange thereon having slid- .inglt in )said'seat member, a valve disk for seati ing en said annular v"seating edge, an annular stem extending outwardly from'said valve disk into the inner end of said sleeve and secured to the seeve whereby'said sleeve will move with said valve disk, a comparatively heavy spring tending to hold said valve disk against said seating edge, said flange being slabbed off at opposite sides to'leave passageway between said sleeve and said seating memberfor ilowof fluid inwardly Vagrainst'rsaid valve diskiorfopening thereoithe outer'end of said'sleeve'formingxa valve housing,

, portseonneetingthe interior ofsaid housing withV theexterior thereoaV check valve in said housing, a springfnormally holding said check valve seated against the outer end of said 'stem for closure of said Yports and said stem against inward ow therethrouglnsaid check valve responding to o utward `flow pressure for opening of said stem passageway and said` ports. Y f

3. A valving assembly for a hydraulic shock absorber comprising an annular valve seat member having an annular seating edge at its inner end, a sleeve extending through said seat member and having a ange thereon having sliding fit in said seat member, a blow oIT valve for seating on said annular seating edgel a hollow stem extending from said blow off valve into the'inner end of said sleeve and secured tothe sleeve for movev ment of the sleeve with the blow off valve, a comparatively heavy spring tending to hold said blow olf valve against said seating edge, said flange Y being slabbed oli at opposite sides to leave passageway between said sleeve vand said seating member for ow of fluid inwardly against Ysaid blow oi valve for opening thereof, the outer end of said sleeve forming a housing having ports connecting the interior thereof with the exterior,

Y a check Valve within said housing anda comparatively light spring for normally holding said check valve to close said ports and tolseat against the-outer; end Vof said stem whereby to prevent inward flow through said ports and said stem, said valve being unseated for outwardilow through said stemand said ports.

4, A valving .assembly for a `hydraulieshock absorber comprising an annular seat member hav,

ing` an annular seating edge.; at its inner end, an annular valve stem structure movablel axially in said seat member and having a guide ange thereon having sliding nt in said seat member,.said valve stern structure terminatingat itsinner end in an annular blow oi valvefor seating.against.y

said seating edge, said guide flange being slabbed oil? at opposite sides to leave passageway between said stem structure and said; seat. member yfor inward flow tending to unseat said vblow 01T valve, a comparatively heavy spring resisting unseating of said blow 01T valve, said stem structure` having an extension on its outerA ,end forming a valve housing having ports. Yconnecting the interior thereof with the exterior; a @heck Valve in said housing and a. light springV normillygholding said cheek valve in position to close said ports andato seatl against said stem structure to prevent inward flow through said ports andy said stem structure, outward flow pressure unseating said valve for outward 4dow through said-stem structure and said ports.v i Y l ,Y

VGflEIRVASlEl M.,; MAGRUM. ,Y -f

BERNARD E; QCONNQR. 

